5D & 4th of July Firework Photos

Here is what the 5D can do with a 17-40 f/4 lens, and tripod when shooting fireworks. I was really happy with these results despite having some trees in the shots. No photoshop was used, but I did crop the shots.

Let me know what you think about the photos as well as the navigation of the photos (are they too large for your screen?)!
Thanks!

One question: When shooting shots of the sky at night, do you simply focus on infinity? At times when using AF and aimed at the sky the lens hunts.